EMU10K1/EMU10K2 driver
This patch changes the emu10k1 multichannel capture device (hw:x,2) to
capture the 16 external inputs by default.  This involves adding DSP
code to route the EXTINs to the FXBUS2 (EFX capture) channels and
setting the corresponding FXWC bits by default.

This allows capturing multiple inputs simultaneously.  It completely
bypasses the capture controls of the mixer.  With my Audigy2 ZS I can
capture LineIn, Line2, and Aux2 at the same time (6 channels).
Signed-off-by: Lee Revell <rlrevell@joe-job.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>